Apparatus for separately adjusting the vapor pressures of two or more substances in a common vapor chamber



Nov. 14, 1967 A.JESTER ETAL 3,353,037 APPARATUS FOR SEPARATELY ADJUSTINGTHE VAPOR PRESSURES OF TWO OR MORE SUBSTANCES IN A COMMON VAPOR CHAMBERFiled May 11, .1964

United States Patent 3,353,037 APPARATUS FOR SEPARATELY ADJUSTING THEVAPOR PRESSURES OF TWO OR MORE SUB- STANCES IN A COMMON VAPOR CHAMBERAlfred Jester, Speyer, Reinhart Langpape, Mannheim, and Josef Bohdansky,Altenbach, Odenwald, Germany, assignors to Brown, Boveri & Cie.,Aktiengesellschaft, Mannheim, Kafertal, Germany, a corporation ofGermany Filed May 11, 1964, Ser. No. 366,348 4 Claims. (Cl. 310-4) Ourinvention relates to method and apparatus for separately adjusting thevapor pressures of two or more substances in a common vapor chamber.

Electronic components that exhibit gas discharge phenomena, for examplethermionic converters such as thermodiodes of the type described andillustrated in Patents No. 2,980,819 and No. 3,054,914, are required tobe filled with substances of varying partial vapor pressuressimultaneously. Thermodiodes of this type serve to transform directlyinto electricity heat energy that is added thereto. They include anemitter for emitting charge carriers and a collector for receiving thesame. The energy required for discharging these charge carriers from theemitter is dependent upon the vapor pressures of the specific gaseoussubstances in the discharge chamber in addition to the temperature.These substances reduce the work necessary to effect the discharge andproduce a small discharge voltage. It is Well known that the elementcesium is particularly well suited for this purpose. These qualities areimproved by adding predetermined amounts of cesium fluoride. Theadvantageous cooperation of both materials is optimum at a ratherspecific ratio of the mixture, that is at a specific partial pressureratio. Since the partial pressures depend upon the temperatureappertaining to the solid or liquid phases of the material, however, itis necessary to make the temperatures of the various substancesindependently adjustable from one another in order to establish orregulate these partial pressures. In the case discussed hereinabove, forexample, the temperature of the cesium fluoride is much higher than thetemperature of the cesium.

It is an object of our invention to provide a method and an apparatusemploying such a method in which the different partial pressures can beadjusted independently from one another by the simplest and least costlymeans.

To this end and according to a feature of our invention, each of thesubstances in the nongaseous, i.e. liquid or solid phase, is heldavailable in separate receptacles communicating with the vapor chamber,and the temperature of each of the receptacles is adjusted according tothe vapor pressure.

Other features which are considered as characteristic for the inventionare set forth in the appended claims.

Although the invention has been illustrated and described as a methodand apparatus for separately adjust ing the vapor pressure of two ormore substances in a common vapor chamber, it is nevertheless notintended to be limited to the details shown, since various modificationsand structural changes may be made therein without departing from thespirit of the invention and within the scope and range of equivalents ofthe claims.

The construction and method of operation of the invention, however,together with additional objects and advantages thereof will be bestunderstood from the following description when read in connection withthe accompanying drawings in which:

FIGS. 1 and 2 are diagrammatic cross-sectional views of diflierentembodiments of the apparatus constructed in accordance with ourinvention and with which the method of our invention is carried out.

Referring now to the drawings and particularly to FIG. 1, there is showna gas-discharge chamber 5 of a thermodiode or similar gas-dischargedevice. The gas-discharge chamber 5 is in communication with a tubularreceptacle 1 and an annular receptacle 2 through the openings 4 and 6respectively. Receptacle 1 contains cesium and the receptacle 2 containscesium fluoride, both of which are thermally volatile, i.e. vaporizeupon suitable heating. The materials in the receptacles diffuse out oftheir respective receptacles into the gas chamber 5 in relation to theirtemperature.

Our invention thus permits another great dilficutly of the knownapparatuses and methods to be overcome. As is well known, only thatsubstance which has the lower temperature is in thermal equilibrium withits vapor. The other substance with the higher temperature diffusescontinuously from the common gas chamber into the cooler receptacle ofthe other substance Where it condenses. In order to minimize the steadyloss of the high temperature substance, the adjustment of the vaporpressure differences must be kept as small as possible by inserting achoke member therebetween.

In accordance with our invention, the receptacle 1, containing thecesium heated to a relatively lower temperature, due to cooling providedby a cooling coil 7, communicates with the vapor chamber 5 of thethermodiode through a very small opening 4. On the other hand, thewarmer receptacle 2 containing cesium fluoride is con- ,nected with thesame vapor chamber through the substantially larger opening 6. Due tothe very small opening 4, only small amounts of the higher temperaturecesium fluoride pass into the cesium storage receptacle 1, so that as aresult of the choking action effected by the small opening 4 the desiredratio of partial vapor pressures is not disturbed. The opening 4 islarge enough, however, to permit predetermined amounts of the coldercesium to pass through. It has been found to be advantageous to providean opening 4 having a cross-sectional area on the order of magnitude ofcm.

The arrangement of the supply receptacles 1 and 2 in accordance with ourinvention, as shown in FIG. 1, permits a temperature difierence to bemaintained in the simplest manner due to heat conduction through thetube 3. The material of which the vaporizing device, and moreparticularly the tube 3, consists, is stainless steel which is resistantto the chemically aggressive cesium and is a relatively good heatconductor. Heat is furnished by the highly heated thermodiode 5 and isconducted through the tube 3 to the receptacles 1 and 2. Naturally, ahigher temperature is produced in the cesium fluoride receptacle 2,which is spaced only slightly from the thermodiode 5, than in thesubstantially farther removed cesium receptacle 1. By supplementalcooling of the tube 3 instead of or in addition to cooling receptacle 2with the cooling coil 7, the temperature difference between bothreceptacles 1 and 2 can be altered within specific limits.

In the embodiment illustrated in FIG. 2, the supply receptacles 1 and 2are located in diflerent connecting tubes 8 and 9 respectively, of thethermodiode. Separate adjustment of the receptacle temperatures, such asby suitable cooling coils, is consequently readily possible with thisembodiment.

Instead of the very small opening 4, the choke action necessary forminimizing the aforementioned gas balancing or equilibrium, produced bythe flow of the higher temperature cesium fluoride vapor into the lowertemperature cesium receptacle, is effected by a porous membrane ordiaphragm of limited permeability consisting of glass or a similarsilicon product, which covers the opening 4' as shown in FIG. 2. Byusing a membrane of this another. The partial vapor pressures of eachsubstance thus remain the same throughout the entire vapor chamber.

It is, of course, self-evident that the method of our invention can alsobe used for more than two substances accordingly.

We claim: 1. Apparatus for separately regulating the vapor pressures ofat least two thermally volatile substances in a chamber, said apparatuscomprising at least two receptacles communicating with the chamber, saidreceptacles respectively containing the substances in non-vaporousphase, means for heating the substances in said receptacles to theirvolatilizing temperatures, and means for adjusting the temperature ineach of said receptacles in accordance with the vapor pressure of therespective substance, the receptacle of relatively lower temperaturecommunicating with the chamber through an opening having a much smallercross section than the opening through which the higher temperaturereceptacle com- .municates with the chamber, whereby the highertemperature vapor in the chamber is choked from entering the lowertemperature receptacle.

2. Apparatus according to claim 1, wherein the opening between saidlower temperature receptacle and the chamber has a cross-sectional areaon the order of magnitude of $6 cm.

3. Apparatus for separately regulating the vapor pressures of at leasttwo thermally volatile substances in a chamber, said apparatuscomprising a connecting tube extending from the chamber and formed withat least two receptacles located at different distances from andcommunicating with the chamber, said receptacles respectively containingthe substances in non-vaporous phase, means for heating the substancesin said receptacles to their volatilizing temperatures, and means foradjusting the temperature in each of said receptacles in accordance withthe vapor pressure of the respective substance, the receptacle ofrelatively lower temperature communicating with the chamber through anopening having a much smaller cross section than the opening throughwhich the higher temperature receptacle communicates with the chamber,whereby the higher temperature vapor in the chamber is choked fromentering the lower temperature receptacle.

4. Apparatus for separately regulating the vapor pressures of at leasttwo thermally volatile substances in a chamber, said apparatuscomprising at least two connecting tubes extending from the chamber,each formed with a receptacle communicating with the chamber, saidreceptacles respectively containing the substances in nonvaporous phase,means for heating the substances in said receptacles to theirvolatilizing temperatures, and means for adjusting the temperature ineach of said receptacles in accordance with the vapor pressure of therespective substance, the receptacle of relatively lower temperaturecommunicating with the chamber through an opening having a much smallercross section than the opening through which the higher temperaturereceptacle communicates with the chamber, whereby the higher temperaturevapor in the chamber is choked from entering the lower temperaturereceptacle.

References Cited UNITED STATES PATENTS 3,215,868 11/1965 Pidd 310-4MILTON O. HIRSHFIELD, Primary Examiner.

LW. GIBBS, ]R., Examiner.

1. APPARATUS FOR SEPARATELY REGULATING THE VAPOR PRESSURES OF AT LEASTTWO THERMALLY VOLATILE SUBSTANCES IN A CHAMBER, SAID APPARATUSCOMPRISING AT LEAST TWO RECEPTACLES COMMUNICATING WITH THE CHAMBER, SAIDRECEPTACLES RESPECTIVELY CONTAINING THE SUBSTANCES IN NON-VAPOROUSPHASE, MEANS FOR HEATING THE SUBSTANCES IN SAID RECEPTACLES TO THEIRVOLATILIZING TEMPERATURES, AND MEANS FOR ADJUSTING THE TEMPERATURE INEACH OF SAID RECEPTACLES IN ACCORDANCE WITH THE VAPOR PRESSURE OF THERESPECTIVE SUBSTANCE, THE RECEPTACLE OF RELATIVELY LOWER TEMPERATURECOMMUNICATING WITH THE CHAMBER THROUGH AN OPENING HAVING A MUCH SMALLERCROSS SECTION THAN THE OPENING THROUGH WHICH THE HIGHER TEMPERATURERECEPTACLE COMMUNICATES WITH THE CHAMBER, WHEREBY THE HIGHER TEMPERATUREVAPOR IN THE CHAMBER IS CHOKED FROM ENTERING THE LOWER TEMPERATURERECEPTACLE.